Myxoviruses, i.e., viruses in orthomyxoviridae and paramyxoviridae families, are RNA viruses. Influenza is in the orthomyxoviridae family. Influenza virus is the leading cause of morbidity and mortality from respiratory disease in North America despite the existence of vaccine prophylaxis. This is due to the fact that the vaccines currently in use reduce illness in approximately 70% of healthy adults when homologous to the prevalent circulating virus, but protection in the elderly reaches only approximately 40%. Vaccine efficacy is reduced substantially when the circulating strains differ from those constituting the vaccine.
Current influenza drugs have limited efficacy. For example, Oseltamivir (Tamiflu) is an antiviral drug that slows the spread of influenza virus. However, it has been reported that Tamiflu offered mild benefits in terms of duration of symptoms for healthy adults if taken within 24 hours of onset of symptoms, but there was no clear evidence it prevented lower respiratory tract infections or other complications of influenza. Thus, there is a need to identify improved methods for treating or preventing influenza infections.
Measles virus (MV), a representative of the paramyxovirus family, is one of the most infectious viruses identified. Despite enhanced efforts for global implementation of a live-attenuated vaccine, MV is a principle cause of morbidity, and infection results in approximately 300,000 to 400,000 deaths annually worldwide, rendering the virus the leading cause of childhood deaths from a vaccine-preventable disease globally. Low vaccination coverage in parts of the developing world and insufficient or declining herd immunity in several developed countries contribute to continued MV activity. In addition to a substantial immunosuppression that lasts several months, complications associated with MV infection include acute encephalitis and subacute sclerosing panencephalitis (SSPE), a late lethal sequela that manifests itself years after the primary infection. Currently, Ribavirin is the only drug approved for the treatment of some paramyxovirus infections. It has been used experimentally against MV but with limited efficacy. Thus, there is a need to identify additional agents to treat or prevent MV.
Yoon et al., J Biomol Screen., 2008, 13(7): 591-608 disclose a high-throughput screening protocol that permits screening against non-attenuated wild type MV strains and identified a panel of candidates.